yThe Mercury sodium atmospheric spectral imager for the MMO spacecraft of Bepi-Colombo

I. Yoshikawa, O. Korablev, S. Kameda, D. Rees, H. Nozawa, S. Okano, V. Gnedykh, V. Kottsov, K. Yoshioka, G. Murakami, F. Ezawa, G. Cremonese

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


The Mercury Sodium Atmosphere Spectral Imager (MSASI) on the Mercury Magnetospheric Orbiter (MMO) of the JAXA/ESA Bepi-Colombo (BC) Mission will address a range of fundamental scientific questions pertaining to Mercury's exosphere. The measurements will provide new information on regolith-exosphere-magnetosphere coupling as well as new understanding of the dynamics governing the exosphere bounded by the planetary surface, the solar wind and interplanetary space. MSASI is a high-dispersion visible spectrometer working in the spectral region near the sodium D2 emission (589 nm), a major constituent of the Mercury exosphere. A single high-resolution Fabry-Perot etalon is used in combination with a narrow-band interference filter to achieve a compact and efficient instrument design. The etalon and filter are extremely stable with respect to long-term aging and temperature variations. Full-disk images of the planet are obtained by means of a single-axis scanning mirror in combination with the spin of the MMO spacecraft. This paper presents an overview of the MSASI and the design of the Fabry-Perot interferometer used as its spectral analyser. It is concluded that:(1)The MSASI optical design is practical and can be implemented without new or critical technology developments.(2)The thermally stable etalon design is based on concepts, designs and materials that have a good space heritage.(3)The MSASI instrument will achieve a high signal-to-noise ratio (SNR) (>10) in the range of 2 K-10 M Rayleigh.

Original languageEnglish
Pages (from-to)224-237
Number of pages14
JournalPlanetary and Space Science
Issue number1-2
Publication statusPublished - 2010 Jan
Externally publishedYes


  • BC mission
  • Fabry-Perot interferometer
  • Mercury's exosphere

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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